Seismic Travel Time Tomography in Modeling Low Velocity Anomalies between the Boreholes

2nd International Conference on Mathematics, Science, Education and Technology

数学;自然科学;教育

Octova, A.^1 ; Sule, R.^2

Mining Engineering Department, Faculty of Engineering, Universitas Negeri Padang, Indonesia^1

Geophysical Engineering Department, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Indonesia^2

关键词: Field parameters;    Inversion process;    Low-velocity anomaly;    Model reconstruction;    Seismic tomography;    Seismic travel time;    Subsurface structures;    Travel time data;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/335/1/012056/pdf
DOI  :  10.1088/1757-899X/335/1/012056

来源: IOP

【 摘 要 】

Travel time cross-hole seismic tomography is applied to describing the structure of the subsurface. The sources are placed at one borehole and some receivers are placed in the others. First arrival travel time data that received by each receiver is used as the input data in seismic tomography method. This research is devided into three steps. The first step is reconstructing the synthetic model based on field parameters. Field parameters are divided into 24 receivers and 45 receivers. The second step is applying inversion process for the field data that consists of five pairs bore holes. The last step is testing quality of tomogram with resolution test. Data processing using FAST software produces an explicit shape and resemble the initial model reconstruction of synthetic model with 45 receivers. The tomography processing in field data indicates cavities in several place between the bore holes. Cavities are identified on BH2A-BH1, BH4A-BH2A and BH4A-BH5 with elongated and rounded structure. In resolution tests using a checker-board, anomalies still can be identified up to 2 meter x 2 meter size. Travel time cross-hole seismic tomography analysis proves this mothod is very good to describing subsurface structure and boundary layer. Size and anomalies position can be recognized and interpreted easily.